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Meet the largest science project in US government history—the James Webb Telescope

Precision? The Webb can detect heat generated by a bumblebee as far away as the Moon.

Lee Phillips
- Mar 25, 2016 12:00 pm UTC

Data and command transmission

The Webb Space Telescope is designed to never need service, and in fact it probably can't be serviced or repaired. The Hubble, specifically designed with astronaut-serviceable components, is currently the only satellite that is capable of being fixed or upgraded while in orbit.

In a conversation with Matt Greenhouse, who joined the project in 1997 and is project scientist for the Webb Telescope science instrument payload, he mentioned that it is not inconceivable that a refueling mission may be dispatched in a decade to extend the life of the Telescope. However, the cost-benefit decision for maneuvers like that would be made at a later date.

The Webb’s location at the L2 Lagrange point would make servicing challenging, but it means that it will always be approximately in the same location with respect to the Earth and always within sight of a ground station. We will be able to talk to the telescope and receive data from it continuously.

The planned mode of operation is to uplink command sequences and downlink data up to twice per day through the Deep Space Network, using ground stations in Australia, Spain, and California. The telescope can execute a sequence of pointing and observing commands autonomously. The Space Telescope Science Institute will upload a week’s worth of commands at one go and can make modifications daily as required.

The telescope will produce about 235 Gigabits of astronomical data every day that will need to be absorbed by the Deep Space Network. This requires a bandwidth higher than 10 megabits per second, a new threshold for communications to the L2 point. To get these high data rates meant changing the frequency used previously for communications through the space network and upgrading the entire communications infrastructure. A side effect of this will be a new communications standard to be used in future missions as well.

On the subject of data, the Webb Telescope will follow the policy in place for the Hubble, which is to embargo data for a one-year “proprietary period” for the benefit of investigators working on funded projects. After that, the data is to be released to the public.

A long struggle

The James Webb Space Telescope almost did not survive the combination of construction delays and the politics of science funding. Congress reacted to a ballooning budget and delays in schedule by nearly canceling it in 2011. Killing it probably would have received some support from scientists themselves.

Given the reality that any particular segment of the science budget is a zero-sum game, any large project will typically drain funds from a collection of smaller research projects. Typically, the victims are efforts in basic science that, while important, may not be easy to explain to the public. They're also unlikely to involve job-creating sub-projects scattered over several states that make them attractive to members of Congress. The Webb Telescope was not immune to this kind of friction, and 18 planetary scientists signed a letter opposing the possibility of its draining funding from other science projects.

Further Reading

But the project has survived these hurdles and is making excellent progress toward its 2018 launch date. Dr. Greenhouse pointed out in our conversation that, since the project’s restructuring in 2011, it has been under budget and on schedule. And as this was being written, the Webb Telescope has passed two milestones: the primary and secondary mirrors are now complete. NASA maintains a set of webcams where you can get a view into the cleanroom to watch the Telescope taking shape, live.

This progress, combined with the fact that it is the largest science project in US government history, has caused other areas of the government to take notice. The Webb Telescope may become a model for the organization of certain types of large government enterprises.

The mission of NASA is not purely science but one of public inspiration as well. The science community is well aware that the large sums of money spent on the International Space Station do not justify, in purely scientific terms, the relatively meager amount of actual research that results. It can be frustrating to contemplate the amount of serious space science that could be supported by the ISS budget.

But it is impossible to quantify the value of the inspiration gained from being able to watch, and talk to, astronauts floating in orbit and taking pictures of Earth. Is there any doubt that there are children in grade school today who are deciding to become scientists because of the men and women flying 249 miles above their heads?

Enlarge/ John Mather and Amber Straughn answering questions about the James Webb Telescope at the AAAS Annual Meeting, February 14th, 2016.

Lee Phillips.

Amber Straughn, the deputy project scientist for James Webb Space Telescope Science Communications, made it vividly clear how much importance NASA attaches to public education and outreach during her presentation at the recent AAAS meeting in Washington. She solved the mystery of why the photographs of telescope assembly on NASA’s websites are so beautiful: they are created by artists, and they are meant to transcend the function of mere laboratory record keeping.

Dr. Straughn also treated the audience to a showing of an amazing time-lapse record of the entire mirror assembly process and a photographic record of the time the DC Beltway was shut down to allow part of the telescope to be transported.

Further Reading

Mather, the physics Nobelist, considers the Webb Telescope “the most important project I could imagine working on." He believes it fits perfectly within NASA's missions, both practical and inspirational. “The public is extraordinarily interested in astronomy because it touches the question of our origins and the meaning of life,” he told Ars by e-mail.

In an age marked by pointless rage and petty obsessions, the James Webb Space Telescope should be a gleaming monument to our noblest aspirations. It will teach us about the origins of our Universe and find answers to questions that we have not yet thought to ask. It is the embodiment, in gold, Kapton, and beryllium, of the defiance of David Hilbert—the last century’s greatest mathematician and one of the creators of the theory of general relativity—a defiance against intellectual surrender that he expressed in words that remain inscribed on his tomb: